<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-07-08</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000701374</issuerCik>
        <issuerName>Six Flags Entertainment Corp</issuerName>
        <issuerTradingSymbol>SIX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001491618</rptOwnerCik>
            <rptOwnerName>BHR Master Fund, Ltd.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BHR CAPITAL LLC</rptOwnerStreet1>
            <rptOwnerStreet2>375 PARK AVENUE, 20TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001491617</rptOwnerCik>
            <rptOwnerName>BHR Capital, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 PARK AVENUE, 20TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001042288</rptOwnerCik>
            <rptOwnerName>VAN DYKE STEVEN A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 PARK AVENUE, 20TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.025 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2010-07-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>700000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2060048</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.025 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2010-07-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>700000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3906062</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held directly by BHR Master Fund, Ltd. (the &quot;Fund&quot;).  As of July 8, 2010, the Fund no longer held more than ten percent (10%) of the outstanding shares of the Issuer's common stock (the &quot;Common Stock&quot;), and is no longer subject to the reporting requirements under Section 16 of the Securities Exchange Act of 1934, as amended, and the related rules promulgated thereunder.  BHR Capital LLC (&quot;BHR&quot;) acts as investment advisor to the Fund, and shares voting and investment control with respect to these securities with the Fund.  Steven A. Van Dyke (&quot;Mr. Van Dyke&quot;) is the Chief Investment Officer of BHR, and controls the voting and investment decisions of BHR.  BHR and Mr. Van Dyke each disclaim beneficial ownership of these shares except to the extent of any pecuniary interest therein and this filing should not be deemed an admission of beneficial ownership for Section 16 purposes or any other purpose.</footnote>
        <footnote id="F2">Of the 3,906,062 shares of Common Stock reported on this Form 4 with respect to BHR and Mr. Van Dyke, 2,760,048 shares are held directly by certain investment funds (including the Fund) to which BHR serves as investment adviser.  The remaining 1,146,014 shares of Common Stock are held by certain funds and accounts for which Bay Harbour Management, L.C. (&quot;Bay Harbour&quot;) serves as investment adviser.  Mr. Van Dyke serves as Managing Principal of Bay Harbour, and may be deemed to have beneficial ownership of all shares reported on this Form 4 that are held by funds and accounts managed by BHR or Bay Harbour.  Mr. Van Dyke disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein.  Mr. Van Dyke also directly holds 287,806 shares of Common Stock that have been previously reported on Form 3.</footnote>
        <footnote id="F3">No investment fund for which BHR or Bay Harbour serves as investment adviser individually holds more than 10% of the outstanding Common Stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Steven A. Van Dyke - as Chief Investment Officer of the Investment Manager of BHR Master Fund, Ltd.</signatureName>
        <signatureDate>2010-07-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Steven A. Van Dyke - as Chief Investment Officer of BHR Capital LLC</signatureName>
        <signatureDate>2010-07-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Steven A. Van Dyke</signatureName>
        <signatureDate>2010-07-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
